Salts of bile acids act as detergents to solubilize and consequently aid in digestion of dietary fats. Bile acids are derived from cholesterol and consequently, removing bile acids can result in reduction in cholesterol. Following digestion, bile acids can be passively absorbed in the jejunum, or reabsorbed by active transport in the ileum. Bile acids which are not reabsorbed are lost.
Reabsorption of bile acids from the intestine conserves lipoprotein cholesterol in the bloodstream. Conversely, blood cholesterol level can be diminished by reducing reabsorption of bile acids.
One method of reducing the amount of bile acids that are reabsorbed is oral administration of compounds that sequester the bile acids and cannot themselves be absorbed. The sequestered bile acids are consequently excreted.
Many bile acid sequestrants, however, do not bind conjugated primary bile acids, such as conjugated cholic acid well enough to prevent substantial portions from being reabsorbed. In addition, the volume of sequestrants that can be ingested is limited. As a result, the effectiveness of many sequestrants to diminish blood cholesterol levels is also limited.
Further, the synthesis of many sequestrants can be limited by the expense and reaction yield associated with preparing suitable precursors. For example, alkylating agents employed to modify polymers can be difficult to prepare. In addition, the ability of an alkylating agent to react with a polymer can also limit the effectiveness of the resulting sequestrant.
A need exists, therefore, for a sequestrant and a method which overcomes or minimizes the referenced problems.